centos中对iptables进行管理实例：

对固定网段进行3306端口开放

-bash-3.2# iptables -I INPUT -s 121.124.152.0/22 -p tcp --dport 3306 -j ACCEPT
-bash-3.2# iptables -I INPUT -s 111.87.191.0/28 -p tcp --dport 3306 -j ACCEPT
-bash-3.2# /etc/init.d/iptables save

-bash-3.2# service iptables restart

linux中iptables初学笔记